/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/

/*
 *  X.509 Certificate Signing Request writing
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */
/*
 * References:
 * - CSRs: PKCS#10 v1.7 aka RFC 2986
 * - attributes: PKCS#9 v2.0 aka RFC 2985
 */

#include "tls/config.h"

#if defined(MBEDTLS_X509_CSR_WRITE_C)

#include "tls/x509_csr.h"
#include "tls/oid.h"
#include "tls/asn1write.h"

#include <string.h>
#include <stdlib.h>

#if defined(MBEDTLS_PEM_WRITE_C)
#include "tls/pem.h"
#endif

/* Implementation that should never be optimized out by the compiler */
static void mbedtls_zeroize(void *v, size_t n)
{
	volatile unsigned char *p = v;
	while (n--) {
		*p++ = 0;
	}
}

void mbedtls_x509write_csr_init(mbedtls_x509write_csr *ctx)
{
	memset(ctx, 0, sizeof(mbedtls_x509write_csr));
}

void mbedtls_x509write_csr_free(mbedtls_x509write_csr *ctx)
{
	mbedtls_asn1_free_named_data_list(&ctx->subject);
	mbedtls_asn1_free_named_data_list(&ctx->extensions);

	mbedtls_zeroize(ctx, sizeof(mbedtls_x509write_csr));
}

void mbedtls_x509write_csr_set_md_alg(mbedtls_x509write_csr *ctx, mbedtls_md_type_t md_alg)
{
	ctx->md_alg = md_alg;
}

void mbedtls_x509write_csr_set_key(mbedtls_x509write_csr *ctx, mbedtls_pk_context *key)
{
	ctx->key = key;
}

int mbedtls_x509write_csr_set_subject_name(mbedtls_x509write_csr *ctx, const char *subject_name)
{
	return mbedtls_x509_string_to_names(&ctx->subject, subject_name);
}

int mbedtls_x509write_csr_set_extension(mbedtls_x509write_csr *ctx, const char *oid, size_t oid_len, const unsigned char *val, size_t val_len)
{
	return mbedtls_x509_set_extension(&ctx->extensions, oid, oid_len, 0, val, val_len);
}

int mbedtls_x509write_csr_set_key_usage(mbedtls_x509write_csr *ctx, unsigned char key_usage)
{
	unsigned char buf[4];
	unsigned char *c;
	int ret;

	c = buf + 4;

	if ((ret = mbedtls_asn1_write_bitstring(&c, buf, &key_usage, 7)) != 4) {
		return (ret);
	}

	ret = mbedtls_x509write_csr_set_extension(ctx, MBEDTLS_OID_KEY_USAGE, MBEDTLS_OID_SIZE(MBEDTLS_OID_KEY_USAGE), buf, 4);
	if (ret != 0) {
		return (ret);
	}

	return (0);
}

int mbedtls_x509write_csr_set_ns_cert_type(mbedtls_x509write_csr *ctx, unsigned char ns_cert_type)
{
	unsigned char buf[4];
	unsigned char *c;
	int ret;

	c = buf + 4;

	if ((ret = mbedtls_asn1_write_bitstring(&c, buf, &ns_cert_type, 8)) != 4) {
		return (ret);
	}

	ret = mbedtls_x509write_csr_set_extension(ctx, MBEDTLS_OID_NS_CERT_TYPE, MBEDTLS_OID_SIZE(MBEDTLS_OID_NS_CERT_TYPE), buf, 4);
	if (ret != 0) {
		return (ret);
	}

	return (0);
}

int mbedtls_x509write_csr_der(mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
	int ret;
	const char *sig_oid;
	size_t sig_oid_len = 0;
	unsigned char *c, *c2;
	unsigned char hash[64];
	unsigned char sig[MBEDTLS_MPI_MAX_SIZE];
	unsigned char tmp_buf[2048];
	size_t pub_len = 0, sig_and_oid_len = 0, sig_len;
	size_t len = 0;
	mbedtls_pk_type_t pk_alg;

	/*
	 * Prepare data to be signed in tmp_buf
	 */
	c = tmp_buf + sizeof(tmp_buf);

	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_x509_write_extensions(&c, tmp_buf, ctx->extensions));

	if (len) {
		MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, tmp_buf, len));
		MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE));

		MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, tmp_buf, len));
		MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SET));

		MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_oid(&c, tmp_buf, MBEDTLS_OID_PKCS9_CSR_EXT_REQ, MBEDTLS_OID_SIZE(MBEDTLS_OID_PKCS9_CSR_EXT_REQ)));

		MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, tmp_buf, len));
		MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE));
	}

	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, tmp_buf, len));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC));

	MBEDTLS_ASN1_CHK_ADD(pub_len, mbedtls_pk_write_pubkey_der(ctx->key, tmp_buf, c - tmp_buf));
	c -= pub_len;
	len += pub_len;

	/*
	 *  Subject  ::=  Name
	 */
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_x509_write_names(&c, tmp_buf, ctx->subject));

	/*
	 *  Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }
	 */
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_int(&c, tmp_buf, 0));

	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c, tmp_buf, len));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c, tmp_buf, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE));

	/*
	 * Prepare signature
	 */
	mbedtls_md(mbedtls_md_info_from_type(ctx->md_alg), c, len, hash);

	pk_alg = mbedtls_pk_get_type(ctx->key);
	if (pk_alg == MBEDTLS_PK_ECKEY) {
		pk_alg = MBEDTLS_PK_ECDSA;
	}

	if ((ret = mbedtls_pk_sign(ctx->key, ctx->md_alg, hash, 0, sig, &sig_len, f_rng, p_rng)) != 0 || (ret = mbedtls_oid_get_oid_by_sig_alg(pk_alg, ctx->md_alg, &sig_oid, &sig_oid_len)) != 0) {
		return (ret);
	}

	/*
	 * Write data to output buffer
	 */
	c2 = buf + size;
	MBEDTLS_ASN1_CHK_ADD(sig_and_oid_len, mbedtls_x509_write_sig(&c2, buf, sig_oid, sig_oid_len, sig, sig_len));

	if (len > (size_t)(c2 - buf)) {
		return (MBEDTLS_ERR_ASN1_BUF_TOO_SMALL);
	}

	c2 -= len;
	memcpy(c2, c, len);

	len += sig_and_oid_len;
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(&c2, buf, len));
	MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(&c2, buf, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE));

	return ((int)len);
}

#define PEM_BEGIN_CSR           "-----BEGIN CERTIFICATE REQUEST-----\n"
#define PEM_END_CSR             "-----END CERTIFICATE REQUEST-----\n"

#if defined(MBEDTLS_PEM_WRITE_C)
int mbedtls_x509write_csr_pem(mbedtls_x509write_csr *ctx, unsigned char *buf, size_t size, int (*f_rng)(void *, unsigned char *, size_t), void *p_rng)
{
	int ret;
	unsigned char output_buf[4096];
	size_t olen = 0;

	if ((ret = mbedtls_x509write_csr_der(ctx, output_buf, sizeof(output_buf), f_rng, p_rng)) < 0) {
		return (ret);
	}

	if ((ret = mbedtls_pem_write_buffer(PEM_BEGIN_CSR, PEM_END_CSR, output_buf + sizeof(output_buf) - ret, ret, buf, size, &olen)) != 0) {
		return (ret);
	}

	return (0);
}
#endif							/* MBEDTLS_PEM_WRITE_C */

#endif							/* MBEDTLS_X509_CSR_WRITE_C */
